Semiconductor device manufacturing, which is a collection of integrated processes, involves many iterations of cleaning and drying steps between various processes. For instance, when a semiconductor substrate or a stack of films are etched into a line and space pattern of a given pitch, the spaces or gaps are thereafter typically filled with an insulating film. Before the gaps are filled with the insulating film, the wafer surface is cleaned to remove any impurities and residues.
In cleaning the wafer after etching, cleaning liquid is supplied onto the wafer surface, followed by a supply of purified water to rinse out the wafer. Then, the wafer is dried to remove the purified water from the wafer surface. A typical drying technique used today is IPA (Isopropyl alcohol) drying in which IPA substitutes purified water on the wafer surface.
However, microfabricated device features etched into high aspect ratios may risk collapses during the drying process by surface tension even when IPA is employed. Thus, there is a need in the industry to minimize the increasing risk of pattern collapse driven by pattern densification.